Roller conveyors are commonly employed for material handling to transport products or equipment from one location to another location. The roller conveyors typically consist of a series of tubular rollers. For certain material handling applications, the rollers are driven by a multi-V belt torque transmitting mechanism. The torque transmitting mechanisms typically engage with a hub or sheave of the rollers. In particular, many conveyor manufactures are now making POLY-V® brand multi-V conveyor belt slave driven roller conveyors because of the distinct advantages of high torque capability, low noise, and an ability to reduce the number of drives in many applications.
Typically, a first roller or directly driven roller in the series of rollers is driven by a motor. Consecutive ones of the rollers after the first roller are slave driven by the first one of the rollers through the use of the multi-V belts. For example, a first multi-V belt engages the first roller to an adjacent second roller or slave driven roller in the series of rollers. As a result, the second roller is driven by the first roller. A second multi-V belt engages the second roller and a third roller or slave driven roller. As a result, the third roller is driven by the second roller. The multi-V belts are continually used to engage adjacent ones of the slave driven rollers in the series of rollers from the first roller or directly driven roller to an end roller in the series of rollers. By employing multi-V belts in the above-mentioned configuration, belt tensioners can be eliminated.
The mechanical efficiency of multi-V belts to facilitate maintaining a rotational speed, and thus a conveyor surface speed, from the directly driven roller to the successive slave driven rollers is advantageous in most applications such as pallet handling applications and container or product handling applications. However, in certain sortation applications, such as singulator conveyor systems, the multi-v belts may be inefficient. Singulator conveyor systems are used for alignment and singulation of packages, goods, and materials. An example of a singulator conveyor system is disclosed in U.S. Pat. No. 9,981,804 and U.S. Pat. No. 5,769,204, the disclosures of which are hereby incorporated herein by reference in their entirety. The singulator conveyor systems may be employed in packaging facilities such as courier facilities so packaging can be identified and automatically processed through sorting equipment. The singulator conveyor systems have skewed, or angled rollers to move the packages to one side of the conveyor system, typically along a guard rail or edge guide.
In a singulator conveyor system, it is desired for the products to be aligned in single file with proper spacing between adjacent ones of the products for proper bar code reading, weighing, or diverting into various shipping lanes. However, the rotational speed of the rollers and the surface speed at the rollers varies from the directly driven roller to the end one of the rollers due to slip of the multi-V belts with respect to the rollers due to a slight inefficiency inherent in the multi-V belts. The rotational speed of and the conveyor surface speed at the slave slave driven rollers successively decreases along the series of rollers from the slave driven roller to the end roller. The decrease in the speeds causes the space between adjacent ones of the products to undesirably decrease. Therefore, it is desired for the speeds of the rollers across the series of rollers to be substantially constant to maintain the desired space between the products traveling on the roller conveyor.
In an attempt to maintain constant speeds, additional motors are employed at intervals along the series of rollers to directly drive additional rollers and convert a slave driven roller into a directly driven roller. For example, a motor may be employed at approximately every eighth roller from the previous directly driven roller. Therefore, in a roller conveyor having twenty-four rollers, three motors are required. Additional motors undesirably increase a cost and a complexity of the roller conveyors and maintenance thereof.
Therefore, it would be desirable to provide a system and method of maintaining a substantially constant surface speed across a series of rollers while minimizing a cost and a complexity of the roller conveyor.